Underreamer



Mary A4 1926. 1,583,073

. Vc3. E. LAwsoN UNDERREMER Filed Nov. 19, 1925' Patented YMay 4, 1926.

UNITED STATES PATENT 'OFFICE'.

C EDWARD LAWSON, OF GARBER, OKLAHOMA.

UNDERREAMER.

Application filed November 19, 1925. Serial No. 70,021.

- l To all whom t may concern:

Be it known that I, C EDWARD LAWSON, a citizen'of the United States, residing at Garber, ,countyf of Garfield, and State Voi? Oklahoma, have invented certain new and useful Improvements in Underreamers, ,of which the following is a'specification.

This invention relatestoimprovements in boring devices and has particular reference to under-reamers used in connection with well casings of oil wells, or the like, for

under-reaming the wall of the well to permit the use of additional tube sections or' casings.

important object of the invention rel sides in the provision of a device lof the above character so constructed that the mud or drillings cannot interfere with its working parts. y n

Another object is to provide means for maintaining certain cutter elements inv retracted or inoperative position during the lowering of thedevice into the casing.

A further object resides inthe particular construction andarrangement of the cutters and the means for preventing their removal from certain associated parts.

Still further objects and advantages of the inventiony will become apparent as the description unfolds, and in order that the same may be better understood reference is had to the accompanying drawing forming a part of this specification.

In said drawings:

Figure 1 is a central longitudinal section of the invention, illustrating the same in op-L erative or working position. Y

Fig. 2 is a view like unto Fig. 1, but showing the parts in inoperative position, or more precisely, as the device appears when being lowered into the casing.

Figa 3 is a transverse section taken on line 3 3 of Fig. 1 to illustrate certain inset blocks carrying pivoted lugs. f i

Fig. 4 is a similar section taken ony line 4 4Y of Fig. .2 to show certainrunners or riders. l l Y Fig. 5 is a transverse sectional view taken on the line 5-5 of Fig. 1; and Fig. 6 is a similar v1ew taken on the plane of the line 6 6 of Fig. v2.

Experience gained by practical men engaged inthe operations of Well-boringfhas taught and demonstratedthe short-comings and disadvantages of vthe under-reamers now ir. use.v Some of these comprised a relatively Vlarge numberv of complicated parts, l easyi broken or disarranged, with the result that said parts .fall-to the bottom of the well, which requlres the tedious operationof-shinglthemV out or a final abandonment of the we their working parts' exposed to the mud and drillings within the l well with the result Still other ofthe under-reamers have y technically termed .a7sub7 and having va plug 13 at its upperfendofor connectionto a string of tools, (not shown). Said lower member 11, which I yterm the body portion, is provided with a longitudinal bore 14, extending from the top of the body 11 and terminating intermediate its ends, as clear-v ly shown inFigs. 1 and'2. The lower end of said body portion 11 isy reduced to form the squared longitudinally extending head 15, thus delining shoulders 16, the purpose thereof will be pointed out hereafter in the specification. y f

Slidably connected to said squared head 15 is a sleeve or tubular member' 1.7, having diametrically opposed slots 18-18 for the reception of pins or screws vlil-,19, which latter engage saidihead 15 and thus permits the reciprocation of sadisleeve 17 on said head 15. 'i .I

A tapered nose or cap 2O closes the botto-1n of said sleeve 17, and is providedwith a central opening 20a-for the reception of the headed rod 21, which extends through said sleeve 17 and the central opening 15a of said head 15 and intovthe bore 14 of said'body 11. The upper end .of said rod 21 carries a piston-like block 22 which is'bored out, as

vindicated at 22a for the reception Oia spring 23, the lower end of the latter abutting the shoulder` 24 in the kbore 14 and being'held in tension when in the position indicated in Fig. 2, by means of nuts 25.

The description thus vfar points out that the sleeve 17 can reciprocate lupon the head 15, such reciprocationbeinglimited by the q the slots.

compressibility of said spring 23 and the screws 19 operating in said slots 18. The slot and screw arrangement has really been introduced as a meansI ofv safety, for in the event said rod 21 should part, the sleeve and its associated parts will be held to said head 15 by said screws abutting the top of This is a feature of some im' portance, since the danger of parts dropping into the well is positively avoided.

Inset blocks 26-26, carrying pivoted lugs 27--27 are positioned within the opposed openings 28;' 23 in said body 11, said lugs being operated by runners or riders 29-29 as will'presently appear. I now direct particular attention to the cutter elements 30, which are provided with a'shank portion 31 pivot-ally mounted in said cap 20 and normally being held in retracted position by means of leaf springs 32-32. These cutters areI each longitudinally grooved to snugly lit about the rod 21 when `v in retracted position, while the projections 33 lie in the path of the head 15. From the base of said projections the tops of the cutters are inclined downwardly, as indicated at 34;, and' mergewith the cutting edges 35.

The base of each cutter is given a double slantedV cut to the sl1a1ikpo1tion`31, the cut 36, adjacent the shank portion and the inclined portion 34C and' also the projection 33 are adapted to fit within opposed slots 37-37 in said sleeve 17 and the shape of said slots in cross-section is an Vexact counterpart of these portions o-f the cutters above referred to. InV other words, when the cutters are expanded, as in Fig. 1, they coincide positively with the slots and by reason of this sealing prevent any mud or drillings from entering said sleeve 17 This feature is not found in the present-day under-rea-mers and those skilled in the art will at once recognize its value.

The foregoing description coverstheV essential parts of'my under-reamer and after due consideration'of the operation, about to follow,it is believed the efliciency and reliability of my improved device will become apparent.

In operation, the device is lowered into a casing in the position as indicated in Fig. 2. 'Ihe block 22 is held in position by the lugs 27 engaging the beveled face 22a by the runners 29,'which latter slide down the casing until they reach the bottom thereof, whereupon they fall into the hole, thus releasing the lugs 27 which assume the position indicated in Fig. 1, permitting the spring to expand and carry upwardly all the parts associated with the rod 21. At this point it may be well to note that since said runners 29 are preferably made of cast iron, they are easily ground up in the hole during the drilling.

y The sleeve 17 now rises bodily upon the head 15, whereupon the first cam surface 38 of said head 15 engages the projections 33 of said cutters, forces them apart, while the second cam surface 39 completely expands .the cutters to the operative positionas indicated in Fig. 1. v

`When the reaming has been completed the device is drawn upward out of the hole, whereupon the tops 34 of the cutters come in contact with the bottom edge of the casing, holding sleeve 17 stationary until the body portion 11 is pulled upward andassumes the position indicated in Fig. 2, com pressing the spring 23 and finally withdrawing the cutters into the sleeve which permits the device to be removed from the well through the casing.n It will be observed that during the lowering and raising operations, the cutters are at all times within the lcon fines of the sleeve 17.

Obviously minor modifications and changes in the device as illustrated may be resorted to liberally which fall within the spirit of the invention or the scope of the ap# pended claims. 1

I claim:

1. An under-reamer comprising a body portion having a longitudinal bore, a tubular member' slidably connected to said body lportion and having side slots, cutters mounted within said tubular member, said cutters having a configuration conforming to said slots in cross-section, a head operatively mounted within said tubular member and having its lower side portions provided with a double-cam surface, and a spring-pressed rod `operating within the bore in said body portion and adapt-ed to force said head yinto engagement with said cutters for expanding the same.

2. An under-reamer comprising a body portion having a longitudinal bore, a tubular member shdably connected to said body portion and having side slots, cutters mounted within said tubular member, a cam-sur faced head operating within said tubular member, a spring-pressed rod operating within the bore in said body portion and adapted to force said head into engagement with said cutters for expanding the same and meansv associated with said body portion -forl holding said springepressed rodv in prising pivoted' lugs adapted `to hold said body portion and said tubular member in meao'va spaced relation and also adapted to release said rod toallow said spring to force said head into engagement with said cutters for expanding the Same.

4. An under-reamer comprising abody portion having a longitudinal bore, a tubular member slidably connected to said body portion, cutters mounted Within said tnbular l member, a cam-surfaced head operating Within said tubular member, spring-pressed 10 cutters for expandingthe same and means carried by the tubular member for retracting 15 said cutters.

In testimony whereof I aiiix my signature.

C EDWARD LAWSON. 

